Add support for logs - used in soo env.

[jmi-reds]

• vlogs frontend driver
• logs function in kernel and usr-space

[clemdiep]

Fast review, didn't looked deeply in implementation yet. Also, correct formats errors reported by clang-format

[daniel-rossier]

I guess we need to understand the relevance of these logs.

[jmi-reds]

the goals of this PR is to add the support of logs when SO3 is used as a Capsule. It means is it only valid when SO3 is used as a capsule in SOO environment: the logs messages are sent to the agency via vlogs frontend/backend and sorted in a specific file (thanks to syslog-ng).

The following picture show an overview of the flow:

I was to focus on agency side and ported/adapted code from emiso project. I missed to better check what was present in SO3 - the LOG macro is new and not present when emiso was created.

so:

• The name logs is not great (it came from Docker container logs cmd...). It can be merged with the LOG macro or a new better name to be find, il possible the same/similar name in usr and kernel space (soo_log, capsule_log, clog`, ...)
• In driver side, yes vlogs is similar to vuart but vuart uses, in Linux, consoles where vlogs does simple printk. It seemed simpler and future proof to create vlogs instead of modify vuart. If vlogs of vuart has to evolve, it will not impact the feature of the other driver.

I will check the new LOG macro and see if and how it can be adapted to support this feature

Side question: Does SO3 have a mechanism to start an application during boot/injection ?

[daniel-rossier]

Yes, SO3 launch init by default, but we can start another. Look at the config file and kernel/main.c

[clemdiep]

New batch of comments